Functional Evaluation Of Normal Kidney By Means Of Gadolinium-DTPA Enhanced Dynamic MRI

Functional Evaluation of Normal Kidney by Means of Gadolinium-DTPA Enhanced Dynamic MRIPurpose To determine the value of dynamic contrast-enhanced MRI in theassessment of the function of normal kidneys. Materials and Methods 15volunteers who underwent abdominal contrast-enhanced MRI without any history of renal and urologic diseases, blood hypertension, Diabetes mellitus, immune system diseases and with normal lab renal function were recruited in our study. MRI was performed using a 1.5-T superconductive magnet system with SE T1WI (TR/TE=500/15ms), FSE T2WI (TR/TE=4000/80ms), and FE T1*WI (TR/TE=80/5ms, flip angle=75°) with breath hold in axial plane to evaluate the morphology of the kidneys, FE T1*WI was also performed in coronal plane with breath hold to evaluate the size of the normal kidney and the thickness of the renal cortex. Dynamic gradient echo sequence FFE (TR/TE=40/5ms, flip angle=25°) was applied after manual bolus injection (via a cubital vein) of 0.1mmol/kg Gd-DTPA. Morphological evaluation was on renal size, cortical thickness, and corticomedullary differentiation (CMD). Functional analysis was performed by evaluating the time-signal intensity curves using the region of interest (ROI) in the upper, middle and lower parts of the cortex and the medulla. Mean peak intensity value (P), time to peak intensity (T), and the P/T ratio at the renal cortex and medulla of each kidney were obtained. The relationship of these parameters to serum creatinine (Scr) and blood urea nitrogen (BUN) was investigated. Results All 30 normal kidneys show clear CMD in FE T1*WI, with the renal size (longitudinal diameter) between 9.1cm to 11.6cm, and the mean thickness of renal cortex was 9.4mm. There were four distinguished phases in the transit of the...